But for the gentle hissing of pythons, Dah Dangbénon's voodoo temple could have been mistaken for a new-age hippy gathering. Seated in a semicircle on fraying raffia mats, devotees listened rapturously as the high priest talked at length about oneness with the cosmos.

"There can be no equilibrium without respecting the universal laws of nature, and our ancient knowledge and traditions," said Dangbénon, a silver-haired man whose toenails were painted an improbable bright pink.

He rolled his eyes exasperatedly when explaining how a faith that expressly forbade killing another human being had been "fetishised" by outsiders. "Voodoo is not about using magic spells to curse your enemies," said Dangbénon, whose clan has for generations overseen this temple dedicated to pythons. "If you choose to manipulate nature to harm your neighbour, it's not voodoo that harms your neighbour, it is you."

Like its Nigerian cousin, juju, voodoo originated in Benin's ancient kingdom of Dahomey. Today the tradition based on nature is so interwoven with daily life that it borders on the banal in Benin. Temples are slotted in between buzzing restaurants and pharmacies, easily overlooked. Tiny carved talismans swing decoratively in doorways where chickens scratch and children dart noisily around. Elders gossiping at roadside bars spill the first sip of each beer to honour the spirits.

About half the country's 9 million people are followers of the mainstream benign form of voodoo, but it has produced extreme practices. In November, officials linked the digging up of 100 graves to an underground trade in human organs for black magic rituals. In the village of Zakpota, deep in the bush, villagers said that twice during especially tough harvest years a young child had "disappeared". "The family was shunned [by villagers]. It is not something people are proud of talking about because it pained us very much," said one villager, Sylvan, who refused to say any more.

But most visitors to Dangbénon's palm thatch temple, bearing bottles of fiery moonshine as a gift, want help to find a job. Healing after bereavement is also high on their list of priorities.

"Colonialists demonised voodoo to the point where even the word makes you think of backwardness, something derogatory. But it's as much a part of African heritage as Buddhism is to Asia, and much older [than Buddhism]. All the good in voodoo has been tainted," Dangbénon said.

In the 1990s, Benin's government overturned a decades-long ban and recognised voodoo as a great cultural tradition, even promoting a national voodoo day. For many, the endorsement was purely cosmetic: the old-time faith had long persisted alongside Islam and Christianity.

At Ouidah, the cradle of voodoo, Benin's first cathedral sits opposite the distinctly shabbier Python temple. According to local lore, the temple's priests helped struggling colonial priests fund the cathedral just over a century ago.

"If there's a voodoo celebration after mass I put on my pagne [traditional dress] and go to the ceremony across the street. Even the cathedral priests come and watch the ceremonies during the annual voodoo festival," said a local man, Hipolite Apovo. Not everyone approves. "Some people went to celebrate the pope's visit to the cathedral last year by heading straight to the temple afterwards. My opinion is either you practise Christianity, or you practise voodoo, or you practise nothing at all. It makes no sense to mix all of them, anyhow," said Nicephore Agontinhlo, pointedly avoiding the stalls of feathers, animal parts and beads at the town's charms market.

But what rankles most in unrecognisable depictions of voodoo by Hollywood and western culture is the erasing of a rich musical and artistic contribution. "My musical inspiration comes from the sato [a ceremonial rhythm] of voodoo. Voodoo instruments and music helped shape the music of Africa," said Vincent Ahehehinnou of the renowned group Orchestre Poly-Rythmo.

Recently, the country's most famous priest decided to take matters into his own hands. Dah Aligbonon Akpochihala, who is in his 60s, started a crash course that allows voodoo devotees to attain priesthood in four months rather than the usual three years. A member of Benin's aristocracy, Akpochihala also takes to the radio – "a medium young and old people understand" – to make sure the tradition is restored to its rightful place. "So long as there is Africa, there will be voodoo. As I've said before, we need to bring voodoo in from the dark," he said in his urban temple, wedged between a beauty parlour and hardware shop, and running a side business in photocopying.

Akpochihala's sermons, in French and local dialect, attract both a French-speaking elite and a less educated underclass. "He is someone who is respected by villagers and kings alike," said a listener, Sessi Tonokoui.

Local adaptations have continued to thrive from Haiti to New Orleans. In Brazil, the world's largest Catholic country, tens of thousands of devotees of the religion known as Candomblé launch tiny candlelit boats out to sea to celebrate the religious new year.

"Some of our incantations are spoken in Yoruba because Candomblé came directly from our African ancestors," said Nivaldo Antonio dos Santos, a priest from the north-eastern state of Bahia, the single biggest final destination of African slaves.

Priests from west Africa sometimes travelled to Brazil to relearn drumming rituals that had been lost to them, Dos Santos said.